Long before the beginning or digital age, people had manually stored data while the ‘data storage’ from time to time might suffer loss due to lack of availability and privacy protection. With the advancement of digital technology, data storage has been an indispensable function in many aspects of modern era. The need for availability and privacy protection remains central to evolving data storage design.
Data not only resides in storage but also appears in transition among communication terminals and users. To provide quality of service and quality of experience, it is also of significant value to transport data that is highly available and securely protected. The service of data transport should meet requirements of availability and privacy protection to satisfy user's demand for quality and experience.
Repetition coding is one approach to providing availability against the event of data loss. One application of repetition code is RAID (redundant array of independent disks). Among variations of RAID, RAID 1 creates one redundant piece of a data stream. For one data stream, RAID thus creates two identical copies to be stored. The space overhead of RAID 1 is 50%, which is high in state-of-the-art storage, and it bears low level privacy protection if no encoding or other measure is further applied to the stored copy.